What are the main components in the GPS tracking system?
I am doing my assignment please tell me if anyone knows.
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The whole earth is divided in to imaginary Latitudes & Longitudes. Where ever u are on this globe except for a few place in Africa... u can be tracked by 2-3 satellites in half an hours.. so what happens is that your small GPS tracking device Tracks the nearest 3 satellites(2 more sophisticated) & with their help calculates the cordinates of the place... after this some devices have a built in map of various locations if your cordinated is on the map you will be pointed out on the map as well... thats why satellite tracking is possible in US (becoz Government has allowed mapping to cordinates) where as not possible in India....
The main components are the reciever - which you carry with you - and a system of sattelites. The reciever uses signals from a minimum of three satellites and trigonometry to calculate latitude and longitude, as well as altitude.
GPS receivers listen to signals from a number of satellites that know exactly where they are at any moment. They send a microwave signal encoded with their own information and a signal generated by an atomic clock. The clock is checked when the satellite flies over an island in the Indian Ocean. When the GPS receiver locks onto at least three of these satellite signals, the processor measures the time difference between the signals, and their doppler shift. This information is then computed together and two possible locations are found. The one that is above the satellites, which are at about 300 miles up, is discarded and the one below the satellites is displayed. The position calculated is in three dimensions, Latitude, Longitude, and height above Earth. The signals from the satellites are sometimes scrambled to confuse enemy use in wartime. Even under the best of conditions, the most accurate information is not available to the general public. The Coast guard has a service along the US Coast and along many rivers and inland lakes that measures the satellite signal as received at precisely known locations. They then transmit a local signal that is called DGPS (Differential GPS) that is added to (or subtracted from) the calculated location. This enables ships to stay in the channel, and also enables surveyors to use GPS signals with great accuracy. In summing up, One needs a, or a lot of microwave receivers. ( A typical GPS unit has a 12 channel receiver), A correllation network to compare all of the signal arrival times to establish location, and a display mechanism that calculates Lat/Long/Height. Hope this helps!
